In the house next door to mine lives a dog called Celia. When Celia’s owners go out and leave her alone in the garden she howls. The sound is almost operatic, a high fluting song of desolation. I work from home so there is no escaping the soundtrack to Celia’s loneliness. Recently I bought a bag of doggie treats and whenever it gets too loud I lean over the fence and drop her a few lumps of processed meat. She goes quiet then. For a while, anyway.

Humans have designed complex ways of measuring their loneliness. The UCLA Loneliness Scale asks a series of questions like ‘How often do you feel you cannot tolerate being so alone?’ and ‘How often do you find yourself waiting for people to call or write?’According to social psychologists, up to a third of the population has experienced acute loneliness at some point in their lives. We also know that loneliness is bad for your health. In fact, the expert literature on loneliness is vast and growing. Yet how often do you hear someone say out loud – I’m lonely.

Celia has no problem expressing her loneliness. She just opens her jaws and out it comes. Humans, on the other hand, try and hide their loneliness, thinking it’s a purely personal problem. According to Emily White, the author of a book called ‘Lonely’ (Harper Perennial), we often view our loneliness as an individual shortcoming. We feel ashamed of it.

Thirty years ago I had a job delivering Meals on Wheels to elderly residents in a public housing high-rise. Most days it was hard to get away from my clients. Many of them were so isolated I was the only human they spoke to all day. They left their transistor radios on all day long, just for the sound of a human voice. They tried to delay my departure with small talk about football and the weather. Yet none of them ever said out loud – I’m lonely.

These days loneliness lurks behind the pages of social media sites like Facebook, Twitter and Instagram. Some people look for a sense of communion by observing and commenting upon the apparently busy lives of others. Others hide their heartache behind frequent postings about their apparently busy lives. They wait for ‘likes’ to assuage their loneliness, the equivalent of doggie treats for humans. You never read a tweet that simply says – I’m lonely.